Circuit breaker



L. c. FlSHER CIRCUIT BREAKER Filed March 31, 1.937

A? on a @5557- INVENTOR.

TTORNE-Y.

Patented Aug. 1940 UNITED STATES PATENT OFFICE 9 Claims.

This application relates to circuit breakers and particularly discloses a circuit breaker of the manual operation plus overload release type.

The breaker herein illustrated includes but four major elements: (1) a contact arm or operating bar having on one end a movable contact adapted to make with a stationary contact, (2) a handle for manually moving the contact arm or bar for manual operation to and from on and off positions and also for manually resetting the breaker in oil position after an overload or automatic release of the breaker, (3) a coiled compression spring which constantly engages the contact arm for providing contact pressure and for insuring proper arm actuation, and (4) a bimetal tripping latch or thermal release element adapted to warp on overload for overload release of the parts.

For an understanding of the breaker herein disclosed, reference should be had to the appended drawing disclosing the same. In this drawing,

Fig. 1 shows the breaker with the parts in on position;

Fig. 2 shows the breaker with the parts in oil? position; this position is also the reset" position for manual reset following overload release;

. Fig. 3 shows the parts in overload released or trip position.

The breaker herein disclosed is mounted within a frame or casing III through whose slot H projects ahandle I2 which is pivotally mounted in the casing or base on a fixed pivot I4 formed on the casing and which has its concealed end provided with a pin l5 adapted to seat in either one of the two notches IB-I'I formed in the edge of a contact arm or operating bar I8 on whose end is a movable contact I9 adapted to make with a stationary contact 28 connected to a conductor binding post 2|. A circuit is established from this binding post through the contacts 2Il and I9, a flexible connector 22, and a bimetal thermal release latch or tripping element '23, to a second conductor binding post 2d, and it is understood that the circuit including these conductors is the circuit which is controlled by movement of the handle I2 and which'is protected on'overload by overload release of the breaker operating through the Contact arm I8 which causes separation of the contacts l82ll.

The disposition of handlepin I5 in one or the other of the two notches IE-I1 of the arm' I8 constitutes one point of connection between the handle I2 and the contact arm I8. Another point of connection between the handle I2 and the bar I8 is established through the medium of position (Fig. 1)

a. bell crank or bridging element 25 which is pivotally connected to the handle I2 and to the cascontact arm I8. On the arm I8, between the points of connection I5 and 26 of the handle and the bar [8 is a bearing 21 surrounded by a coiled compression spring 28 which has an end surrounding a pin 29 fixed to the casing, the spring thus being operatively connected to the arm It and bearing on the base l0 and positively and permanently engaging the arm, between the handle-arm connection points, for contact pressure.

Inasmuch as the fixed pin I4 is the only fixed pivot in the breaker and inasmuch as this pivot does not directly form a pivotal bearing for the arm I8, it can readily be seen that the arm I8 floats on three points, (1) a handle-arm connection point, (2) the spring 28, and (3) the latch 23.

The operation of the breaker herein disclosed is as follows: Assume the parts to be in on If the handle I2 be moved clockwise to the position of Fig. 2, pin I5 will cause the arm I8 to rotate counterclockwise on latch 23 as a pivot. In the initial part of the handle movement, spring 28 resists movement of the contact arm I8; in the latter part of the handle movement, spring 28 provides a resilient influence towards contact separating movement of the arm l8; such double functioning of they spring produces a simulated quick break action. I For closing the circuit manually, the arm I8 is rotated counterclockwise from the position of Fig. 2 so that pin I5 relieves the contact arm of' the handle influence, thus permitting spring 28 to cause the arm to rotate clockwise about its latch held point as a pivot to closing position, Fig. 1.

Thus it will be seen that circuit opening is caused by the handle aided by the spring; and that circuit closing is caused by the spring as permitted by movement of the handle.

If the parts are in "on position (Fig. 1) and an overload arises,- the latch 23 warps to the right and releases bell crank 25 and with it the arm [8 so that the spring 28 can open the circuit by moving the arm I8 counterclockwise on the handle connection point I5l6 as a pivot. Such action of the parts automatically causes the handle' I2 to move out of its on position to the trip position whereby the trip of the breaker is indicated by the changed position of the handle.

For manual 'reset of the breaker following trip, handle I2 is rotated clockwise from the trip posig aaiavaa crank 25 and force it to'the latch engaged position of Figs. 1 and 2 where the hookedend 3| of the bell crank is-caught and held by the tip of the latch 23, with such movement being against lo the influence oi the spring 2% so that such movement encounters some slight resistance by such spring. During such movement of the handle and the bell crank 25, the spring 25, coupled with the shifting of the pin l5 from the on position (notch it) to the "01? position (notch ll) of Fig. 2, prevents the contact arm from going into the on position despite the movement of the bell crank as into the on position. Thus reset of the parts, with the parts in circuit open posiac tion, and with the handle ready'tobe given a movement to its on" position for circuit closing,

is accomplished.

In normal manual operation the handle and the contact arm are the only parts that move and their movementis controlled by the spring 28. On overload release operation the latch releases the contact arm and the latter is moved directly, and without movement of intervening parts, by the spring 28, inasmuch as the spring bears diadrectly on the contact arm. This contrasts the present breaker with breakers now known where a complicated linkage between the spring and the contact arm requires. movement following trip of the latch on overload, before the contact arm 85 is moved to open circuit pontion; by the spring.

Now having described the breaker hereof, reference will be had to the claims which follow for a determination of the inventions sought to be protected herein. M I claim: 1

1. A circuit breaker having a contact arm provided with a contact on one end thereof, resilient rotated about one of the handle-arm connection points as a .pivot by the resilient means to a released position, the handle then automatically rotating out of "on position and into a trip position, between which and the oil positiomis the on position. 2. A circuit breaker having a contact arm provided with a contact on one end thereof, resilient means providing a shiftable bearing therefor and pressure thereon, a handle, means operatively connecting the handle to the arm at spaced points go on opposite sides of the bearing, and a bimetal latch holding the arm and engaging it, release of the latch on overload permitting the arm to V be rotated about one, of the handle-arm connection points as a pivot by the resilient means to a as released position, the handle then automatically 'rotatingout of "021 position and into a trip position, between which and the o position,-

is the on position, reset of the arm in ofi position thereafter being accomplished by movem ment of the handle manually from trip" position at least to ofi' position and far enough so 'that the other handle arm connection point causes the arm to be caught and held by the latch, the arm, during such movement of the handle, being prevented from going into on position by virtue of the first-mentioned handlearm connection and the movement or the handle out of on position and at least to ofi" position.

3. A circuit breaker having a contact arin pro- 5 vided with a contact on one end thereof, resilient means providing a shiftable bearing therefor and pressure thereon, a handle, means operatively connecting the handle to the arm at spec points on opposite sides of the bearing, and a etal 10 latch holding the arm and engaging it, movement of the handle from on position to ofi position causing the arm to be rotated about the latch as a pivot, return of the handle from oilto on position permitting the arm to be ro- 15 tated about tlie latch as a pivot by the resilient means, release of the latch on overload permitting the arm to be rotated about one of the handlearm connection points as a pivot by the resilient means to a released position, the handle then automatically rotating 'ont of o position and into a trip position, between which and the ofi position, is the on position, reset of the arm in ofi position thereafter being accomplished by movement of the handle manually from 25 trip position at least to ofi position and far enough so that the other handle-arm connection point causes the arm to be caught and held by the latch, the arm, during such movement of the handle, being prevented from going into on position by virtue of the first mentioned handle-arm connection and the movement or'the handle out oi "on position and at least to of? position.

4. In a circuit breaker, a stationary contact,. a circuit current responsive latch, a contact-arm as having a contact for engaging the stationary contact, a handle means providing a connection between the handle and the arm whereby the handle may move the arm out of 021" position,

7 and a link connecting the handle and arm indeso.

support so as to move the-arm contact towards c5 the stationary contact when the link is held by the latch and to press the arm contact against the stationary contact when the latch holds the link, and for moving the arm contact away from the stationary contact upon latch release, the so handle operatingior moving the arm, about the link as a pivot, so that the arm contact leaves the stationary contact, and also operating for permitting the arm to be moved, about the link as a pivot, by the spring so that the arm contact 55 approaches the stationary/ contact, the. handle also operating for moving the link into latch engaged position following latch release.

5. In a circuit breaker, a stationary contact, a circuit current responsive latch, a contact arm having a contact for engaging the stationary contact, a handle means providing a connection between the handle and the arm whereby the handle may move the arm out of on position, and a link connecting the-handle and arm independ c5 ently of the first named connection to support the arm, and having a part to be engaged by the latch, and a spring, the spring having a constant tendency to rotate the arm on its ind; support so as to move the arm contact towards the stationary contact when the link is'held by the latch and to press the arm contact against the stationary contact when the latch holds the link, and for moving the arm contact away from the stationary contact upon latch release, the handle operatid ing for moving the arm, about the link as a pivot, so that the arm contact leaves the stationary contact, and also operating for permitting the arm to be moved, about the link as a pivot, by the spring so that the arm contact approaches the stationary contact, the handle also operating for moving the link into latch engaged position following latch release, without moving the arm contact against the stationary contact.

6. In a circuit breaker, a stationary contact, a circuit current responsive latch, a contact arm having a contact for engaging the stationary contact, a handle means providing a connection between the handle and the arm whereby the handle may move the arm out of on position, and a link connecting the handle and arm independently of the first named connection to support the arm, and having a part to be engaged by the latch, and a spring, the spring having a constant tendency to rotate the arm on its link support so as to move the arm contact towards the stationary contact when the link is held by the latch and to press the arm contact against the stationary contact when the latch holds the link, and for moving the arm contact away from the stationary contact upon latch release, the handle operating for moving the arm, about the link as a pivot, so that the arm contact leaves the stationary contact, and also operating for permitting the arm to be moved, about the link as a pivot, by the spring so that the arm contact approaches the stationary contact, the handle also operating for moving the link into latch engagd position following latch release, the first named connection between the arm and handle being at one end of the arm, with the second named connection between the arm and handle, through the link, being between the ends of the arm, the arm contact being at the other end of the arm.

'7. In a circuit breaker, a stationary contact, a circuit current responsive latch, a contact arm having a contact for engaging the stationary contact, a handle means providing a connection between the handle and the arm whereby the handle may move the arm out of on position, and a link connecting the handle and arm independently of the first named connection to support the arm, and having a part to be engaged by the latch, and a spring, the spring having a constant tendency to rotate the arm on its link support so as to move the arm contact towards the stationary contact when the link is held by the latch and to press the arm contacts against the stationary contact when the latch holds the link, and for moving the arm contact away from the stationary contact upon latch release, the handle operating for moving the arm, about the link as a pivot, so that the arm contact leaves the stationary contact, and also operating for permitting the arm to be moved, about the link as a pivot, by the spring so that the arm contact approaches the stationary contact, the handle also operating for moving the link into latch engaged position following latch release, the first named connection between the arm and handle being at one end of the arm, with the second named connection between the arm and handle, through the link, being between the ends of the arm, the arm contact being at the other end of the arm, the arm moving about its end handle connection on latch release and about its intermediate handle connection when the latch holds the link.

8. A spring actuated circuit breaker having a contact arm, a handle connected thereto and movable into three separate and readily distinguishable positions, on, off, and tripped and a latch for holding the arm, the latch controlling movement of the parts into tripped position and the handle controlling movement of the parts to and from on and off positions, and operable by movement in one direction from tripped position to the ofi position for resetting the parts in the off position after they have moved to the "tripped position, the parts being so arranged that on position of the handle is between ofi and tripped positions.

9. A spring actuated circuit breaker having a contact arm, a handle connected thereto and movable into three separate and readily distinguishable positions, on, ofif, and "tripped, and a latch for holding the arm, the latch controlling movement of the parts into tripped position and the handle controlling movement of the parts to and from on and off positions, and operable by movement in one direction from trippedposition to the off position for resetting the parts in the off position after they have moved to the tripped position, the parts being so arranged that o position of the handle is between off and tripped positions, the contact' arm being moved by the spring about its latchheld part as a pivot when the handle is moved and about its handle-held part as a pivot when the latch releases.

LYMAN C. FISHER. 

